Finding the Third Proportional to 639,388 and 1,378,496

Step by Step Solution

1. Step 1: Write the proportion equation
   639,388 : 1,378,496 = 1,378,496 : x
2. Step 2: Convert to fraction form
   639,388/1,378,496 = 1,378,496/x
3. Step 3: Cross multiply
   639,388x = 1,378,496 × 1,378,496
4. Step 4: Simplify right side
   639,388x = 1,900,251,222,016
5. Step 5: Solve for x
   x = 1,900,251,222,016/639,388
6. Step 6: Final answer
   x = 2,971,984.49